Spinal construct system

ABSTRACT

Embodiments for a spinal construct system including a spinal fixation plate attachable to fixture element in end-to-end fashion with a coupling mechanism that axially and torsionally constrains the first and second rods to one another. In one form, the end-to-end attachment arrangement is aligned along a common axis of the rods. In another form, the axes of the rods are offset laterally relative to one another.

BACKGROUND

The spine is subject to various pathologies that compromise its loadbearing and support capabilities. Such pathologies of the spine include,for example, degenerative diseases, the effects of tumors and, ofcourse, fractures and dislocations attributable to physical trauma. Inthe treatment of diseases, malformations or injuries affecting spinalmotion segments (which include two or more adjacent vertebrae and thedisc tissue or disc space therebetween), and especially those affectingdisc tissue, it has long been known to remove some or all of adegenerated, ruptured or otherwise failing disc. It is also known thatartificial discs, fusion implants, or other interbody devices can beplaced into the disc space after disc material removal. Externalstabilization of spinal segments other external stabilization deviceshave been helpful in the stabilization and fixation of a spinal motionsegment, in correcting abnormal curvatures and alignments of the spinalcolumn, and for treatment of other conditions.

While external rod systems have been employed along the vertebrae, thegeometric and dimensional features of these rod systems and patientanatomy constrain the surgeon during surgery and prevent optimalplacement and attachment along the spinal column. For example,elongated, one-piece rods can be difficult to maneuver into positionalong the spinal column, and also provide the surgeon with only limitedoptions in sizing and selection of the rod system to be placed duringsurgery.

SUMMARY

The present invention relates to embodiments for a spinal constructsystem having a first spinal fixation element attachable to a secondspinal fixation element in end-to-end fashion with a coupling mechanismthat axially and torsionally constrains the first and second rods to oneanother. In one embodiment the spinal constructs system includes aspinal fixation plate attachable to fixture element in end-to-endfashion with a coupling mechanism that axially and torsionallyconstrains the first and second elements to one another. In one form,the end-to-end attachment arrangement is aligned along a common axis ofthe elements. In another form, the axes of the elements are offsetlaterally relative to one another.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a portion of one embodimentspinal construct system;

FIG. 2 is a perspective view of the spinal construct system of FIG. 1assembled;

FIG. 3 is an exploded elevational view of the spinal construct system ofFIG. 1;

FIG. 4 is a view of a first rod rotated 180 degrees about itslongitudinal axis from its FIG. 3 orientation;

FIG. 5 is a section view of the spinal construct system of FIG. 1assembled with the engaging member removed from the coupling mechanism;

FIG. 6 is an exploded elevation view in partial section of anotherembodiment spinal construct system;

FIG. 7 is an exploded elevation view in partial section of anotherembodiment spinal construct system;

FIG. 8 is an exploded elevation view of another embodiment spinalconstruct system with two embodiments of a coupling mechanism forcoupling the rods to one another;

FIG. 9 is an exploded perspective view of a portion of another spinalconstruct system;

FIG. 10 is an assembled perspective view of the spinal construct systemof FIG. 9;

FIG. 11 is an exploded perspective view of a portion of another spinalconstruct system;

FIG. 12 is an assembled perspective view of the spinal construct systemof FIG. 11;

FIG. 13 is an exploded perspective view of a portion of another spinalconstruct system;

FIG. 14 is an assembled perspective view of the spinal construct systemof FIG. 13;

FIG. 15 is an exploded perspective view of a portion of another spinalconstruct system;

FIG. 16 is an assembled perspective view of the spinal construct systemof FIG. 15;

FIG. 17 is an exploded perspective view of a portion of another spinalconstruct system;

FIG. 18 is an assembled perspective view of the spinal construct systemof FIG. 17;

FIG. 19 is an exploded perspective view of one embodiment of a spinalconstruct system;

FIG. 20 is an exploded perspective view of one embodiment of a spinalconstruct system;

FIG. 21 is an exploded perspective view of one embodiment of a spinalconstruct system;

FIG. 22 is an exploded perspective view of one embodiment of a spinalconstruct system; and

FIG. 23 is an exploded perspective view of one embodiment of a spinalconstruct system.

FIG. 24 is an exploded perspective view of one embodiment of a spinalconstruct system.

DETAILED DESCRIPTION

The present invention relates to embodiments for a spinal constructsystem having a first spinal fixation element attachable to a secondspinal fixation element in end-to-end fashion with a coupling mechanismthat axially and torsionally constrains the first and second elements toone another.

In FIG. 1 there is shown a spinal construct system 10 including a firstrod 12 and a second rod 30. First rod 12 and second rod 30 arereleasably coupled to one another in end-to-end fashion with a couplingmechanism 28. Coupling mechanism 28 includes a coupling body on one ofthe first and second rods 12, 30 and a coupling member on the other ofthe first and second rods 12, 30. The coupling mechanism 28 isconfigured to secure rods 12, 30 to one another in end-to-end fashion.This minimizes the footprint or intrusiveness of the coupling mechanisminto the tissue surrounding the rod system, and maximizes the length ofthe rod portion of each rod available for positioning and/or attachmentalong the spinal column.

First rod 12 includes a first rod portion 14 and coupling member 16 at afirst end of first rod portion 14. Rod portion 14 extends from couplingmember 16 to an opposite second end 17 (FIG. 5.) Second rod 30 includescoupling body 34 at a first end thereof. Rod portion 32 extends fromcoupling body 34 to an opposite second end 35 (FIG. 5.) One or both ofthe second ends 17, 35 of rod portions 14, 32 may include a couplingmember, a coupling body, or simply provide a terminal end shaped likethe corresponding rod portion 14, 32 as shown. In the embodimentsillustrated herein, although only one coupling mechanism is shown, oneor more of the first and second rods can be adapted for engagement withanother rod at each end thereof so that three or more rods may comprisethe rod system. The rod portions can be secured to vertebrae of thespinal column system with any one or combination of hooks, screws,bolts, multi-axial screws, staples, cables or wires, sutures, clamps,and/or other attachment devices and systems, with or without interbodyfusion devices or implants between vertebrae.

The first rod portion can be provided with a characteristic that differsfrom a characteristic of the second rod portion. The coupling mechanismallows rods of differing characteristics and rods having the samecharacteristics to be secured to one another in end-to-end fashion toprovide a rod system that is adapted for the anatomy, surgicalcondition, or surgical procedure. In one embodiment, the characteristicincludes a cross-sectional dimension of the rod portions. Otherembodiments contemplate selection criteria for selection and assembly ofthe rod portion to include any one or combination of characteristics,including length, contouring, flexibility, surface features, shape,section modulus, elasticity, materials and material properties, andcoatings, for example. For example, in one embodiment a first rodprovides a rigid support between a first set of anchors, while thesecond rod is flexible to provide dynamic stabilization between a secondset of anchors. The second rod can be in the form of a tether, cablewire, spring, bumper, or other motion permitting construct.

As shown in FIGS. 1-2 and 5, rod portion 14 extends along longitudinalaxis 11 and includes a first cross-sectional dimension 22 betweenopposite sides thereof transverse to longitudinal axis 11. Similarly,rod portion 32 extends along longitudinal axis 11 and includes a secondcross-sectional dimension 40 between opposite sides thereof transverseto longitudinal axis 11. In the illustrated embodiment, cross-sectionaldimension 22 corresponds to a diameter of a cylindrical rod portion 14that is smaller than a diameter corresponding to cross-sectionaldimension 40 of a cylindrical rod portion 32. In one specificapplication, the diameter of first rod portion 14 is sized to extendalong a first portion of the spine, such as the cervical region, and thediameter of second rod portion 32 is sized to extend along a secondportion of the spine, such as the thoracic region. Other systemscontemplate multiple rod portions coupled to one another in end-to-endfashion with characteristics adapted for positioning along any one orcombination of the sacral, lumbar, thoracic and cervical regions of thespinal column.

Coupling member 16 includes a threaded outer surface extending from rodportion 14 to an end member 20 lacking threads. Coupling member 16further includes a contact portion 18 along at least one side thereof,as also shown in FIG. 3. Contact portion 18 can be formed by a cutoutproviding a flat surface extending along coupling member 16. Contactportion 18 can also include a concave surface, a convex surface, areceptacle, or other suitable configuration for contacting an engagingmember. As shown in FIG. 5, the thread pattern of coupling member 16extends completely therearound between the opposite sides of contactportion 18. Other embodiments contemplate that multiple contact portionsare provided along coupling member 16 to provide multiple engagementlocations for engaging member 42, as discussed further below.

Coupling body 34 can be enlarged relative to rod portion 32 to provide aflange or hub to which coupling member 16 can be releasably engaged. Inthe illustrated embodiment, coupling body 34 is a cubic block, althoughother shapes are also contemplated, such as rectangular, cylindrical andnon-uniform shapes. Coupling body 34 includes a first bore 36 formedinternally therein that extends along and opens along longitudinal axis11 at an end of coupling body 34. Coupling body 34 further includes asecond bore 38 extending therein transversely to first bore 36. Asfurther shown in FIG. 5, second bore 38 can be internally threaded forreceipt of an engagement member. Second bore 38 can also be orthogonalto first bore 36, although other orientations are also contemplated.

As shown in FIGS. 2 and 5, rods 12, 30 can be assembled in end-to-endfashion and aligned along longitudinal axis 11 with coupling member 16received in bore 36 and axially constrained by threaded engagement withcoupling body 34. End member 20 facilitates positioning and alignment ofcoupling member 16 in bore 36, preventing or reducing the possibility ofcross-threading coupling member 16 with coupling body 34. The axial loadbetween rods 12, 30 is carried by the engagement between coupling member16 and coupling body 34, which are also aligned along the axis 11 of rodsystem 10 when engaged. Accordingly, torsional loading of the componentsof rod system 10 is minimized since the rods 12, 30 are connected to oneanother in end-to-end fashion along axis 11. Furthermore, the footprintof coupling mechanism 28 both transversely to rods 12, 30 and along rods12, 30 is minimized, making the procedure for positioning rod system 10less invasive, providing additional rod length for contouring andattachment of fasteners for engagement with the spinal column, andminimizing the number of components employed in securing the rods 12, 30to one another.

Engaging member 42 is positionable in second bore 38 and engageable tocoupling member 16 to prevent rod 12 from disengaging from rod 30. Inone embodiment, contact portion 18 of coupling member 16 is orientedtoward second bore 38, and engaging member 42 is an externally threadedset screw 44 engageable in second bore 38. A tool engaging recess 46 isprovided for engagement with a tool, such as a hex driver, to allow theset screw 44 to be driven into second bore 38. Set screw 44 is driveninto second bore 38 so that end 48 is in contact with contact portion18, preventing coupling member 16 from rotating in body 34 and resistingtorsional loading between rods 12, 30.

With contact surface 18 aligned with bore 38, the rod portions 14, 32are oriented in a predetermined alignment with one another determined bythe location of contact surface 18 and bore 38 relative to therespective rod portions 14, 32. For example, if one or both of rodportions 14, 32 are provided with non-circular cross-sections,through-holes, or other characteristic along their respective lengths,the characteristics can be oriented relative to contact surface 18and/or bore 38 so that when contact surface 18 is engaged by engagingmember 42, the characteristic of rod portion 14 is positioned in adesired alignment relative rod portion 32. In this manner, the rodportions 14, 32 can be secured with these characteristics in apredetermined alignment relative to one another, and maintained in thisalignment by the engagement of engaging member 42 with contact surface18.

Other embodiments contemplate other arrangements for coupling mechanism28. For example, engaging member 42 can be a pin that is received in ahole or recess in coupling member 16. Coupling body 34 can be a nutrotatably captured on the end of rod portion 32. Coupling mechanism 28can include a bayonet locking type device, or a spring-biased ballplunger in coupling member 16 that is received in a detent in couplingbody 34.

In FIG. 6, there is shown another embodiment rod system 110 extendingalong a longitudinal axis 111 and including a first rod 112 having rodportion 114 and coupling member 116. A second rod 130 includes rodportion 132 and a coupling body 134 with an axial bore 136. First andsecond rod portions 114, 132 can be provided with differingcharacteristics and axially constrained to one another in end-to-endfashion. Body 134 does not include a second bore for an engaging member,and coupling member 116 can be provided completely threaded therearound.To torsionally constrain coupling member 116 in coupling body 134,coupling member 116 can be provided with locking threads to preventfirst and second rods 112, 130 from rotating relative to one another. Inanother embodiment, a simple threaded engagement is provided to axiallyconstrain rods 112, 130 to one another, and relative rotation of rods112, 130 is resisted by the engagement of rods 112, 130 to the spinalcolumn.

In FIG. 7, there is shown another embodiment rod system 210 including afirst rod 212 and a second rod 230 extending along a longitudinal axis211. First rod 212 includes a first rod portion 214 and second rod 230includes a second rod portion 232. First and second rod portions 214,232 can be provided with differing characteristics and attached to oneanother in end-to-end fashion with a coupling mechanism 228. First rod212 includes a coupling member 216 at an end of rod portion 214.Coupling member 216 is externally tapered toward the first end 220 ofrod 212, and forms a lip 218 extending about rod portion 214. Couplingbody 234 includes an axial bore that is tapered from a first end 238 ofsecond rod 230 toward rod portion 232. Engaging member 216 is press fitinto bore 236 so that the tapered outer surface is received in theflared bore to frictionally engage and axially and torsionally constrainfirst rod 212 to second rod 230 in end-to-end fashion. It is furthercontemplated that an engaging member can be provided extending betweencoupling body 234 and coupling member 216 to provide additional fixationin addition to the friction fit between coupling body 234 and couplingmember 216.

In FIG. 8, there is shown another embodiment rod system 310 including afirst rod 312 and a second rod 330 extending along longitudinal axis311. First rod 312 includes a first rod portion 314 and second rod 330includes a second rod portion 332. First rod 312 includes a couplingmember at an end of rod portion 314 in the form of a flange or hub 316extending around first rod portion 314. Flange 316 forms a lip 318extending about rod portion 314. Second rod 330 includes a coupling bodyat an end thereof that is also in the form of a flange or hub 334.Flange 334 extends around and forms a lip 336 about second rod portion332. Flanges 316, 334 are positionable in abutting engagement with oneanother in end-to-end fashion so that rods 312, 330 having differingcharacteristics can be secured to one another to provide rod system 310.Coupling mechanism 328 includes a fastener 340 extendable throughaligned bores 320, 338 extending parallel to axis 311 through theflanges 316, 334. A nut 342 is engageable with fastener 340 to axiallyconstrain rods 312, 330 together in end-to-end fashion. It iscontemplated that a number of fasteners can be positioned about theflanges to provide additional axial constraint and also torsionalconstraint to rods 312, 330. Although fastener 340 has been shown as abolt with a nut, other fasteners are also contemplated, includingrivets, screws, and bolts threadingly engaged to the flange bores, forexample.

Another embodiment coupling mechanism 428 is shown in FIG. 8 thatincludes a clamping member 430 and an engaging member 432. Clampingmember 430 includes arms 434, 436 at opposite ends thereof that extendalong adjacent ones of the flanges 316, 334. Fastener 432 extendsparallel to axis 311 and is engageable to a bore 438 in arm 434.Fastener 432 is positionable in contact with flange 316 to bias arm 436into contact with flange 334. Flanges 316, 334 are drawn toward oneanother to position the flanges in end-to-end contact and axiallyconstrain rods 312, 330 relative to one another. It is contemplated thata number of clamping members can be provided about flanges 316, 334 toprovide a secure clamping arrangement to prevent rods 312, 330 frompivoting or splaying relative to one another. It is further contemplatedthat clamping member 430 can be sized to extend along a portion of theperimeter of flanges 316, 334, and a number of fasteners 432 areprovided to clamp first and second rods 312, 330 to one another.

In FIGS. 9-10 there is shown a spinal rod system 510 including a firstrod 512 and a second rod 530. First rod 512 and second rod 530 arereleasably coupled to one another in end-to-end fashion with a couplingmechanism 528. Coupling mechanism 528 includes a coupling body 534releasably engageable to each of the first and second rods 512, 530. Thecoupling mechanism 528 is configured to secure rods 512, 530 to oneanother in end-to-end fashion while minimizing the footprint orintrusiveness of the coupling mechanism into the tissue surrounding therod system and maximizing the length of the rod portion of each rodavailable for positioning and/or attachment along the spinal column.

First rod 512 includes a first rod portion 514 and coupling member 516at a first end of first rod portion 514. Rod portion 514 extends fromcoupling member 516 to an opposite second end (not shown.) Second rod530 includes coupling member 552 at a first end thereof. Rod portion 532extends from coupling member 516 to an opposite second end (not shown.)One or both of the second ends of rod portions 514, 532 may include acoupling member, a coupling body, or simply provide a terminal endshaped like the corresponding rod portion 514, 532 as shown.

First rod portion 514 can be provided with a characteristic that differsfrom a characteristic of second rod portion 532. The coupling mechanism528 allows rods of differing characteristics to be secured to oneanother in end-to-end fashion to provide a rod system that is adaptedfor the anatomy, surgical condition, or surgical procedure. In oneembodiment, the characteristic includes a cross-sectional dimension ofthe rod portions 514, 532. Other embodiments contemplate selectioncriteria for selection and assembly of the rod portion to include anyone or combination of characteristics, including length, contouring,flexibility, surface features, shape, section modulus, elasticity,materials and material properties, and coatings, for example.

As shown in FIGS. 9-10, rod portion 514 extends along longitudinal axis513 and includes a first cross-sectional dimension 522 between oppositesides thereof transverse to longitudinal axis 513. Similarly, rodportion 532 extends along longitudinal axis 531 and includes a secondcross-sectional dimension 540 between opposite sides thereof transverseto longitudinal axis 531. In the illustrated embodiment, cross-sectionaldimension 522 corresponds to a diameter of a cylindrical rod portion 514that is smaller than a diameter corresponding to cross-sectionaldimension 540 of a cylindrical rod portion 532. In one specificapplication, the diameter of first rod portion 514 is sized to extendalong a first portion of the spine, such as the cervical region, and thediameter of second rod portion 532 is sized to extend along a secondportion of the spine, such as the thoracic region. Other systemscontemplate multiple rod portions coupled to one another in end-to-endfashion with characteristics adapted for positioning along any one orcombination of the sacral, lumbar, thoracic and cervical regions of thespinal column.

Coupling member 516 includes a threaded outer surface extending from rodportion 514 to an end member 520 lacking threads. Coupling member 516further includes a contact portion 518 along at least one side thereof.Contact portion 518 can be formed by a cutout providing a flat surfaceextending along coupling member 516. Contact portion 518 can alsoinclude a concave surface, a convex surface, a receptacle, or othersuitable configuration for contacting an engaging member. The threadpattern of coupling member 516 can extend completely therearound betweenthe opposite sides of contact portion 518. Other embodiments contemplatethat multiple contact portions are provided along coupling member 516 toprovide multiple engagement locations for engaging member 542, asdiscussed further below.

Rod 530 similarly includes a coupling member 552 including a threadedouter surface extending from rod portion 532 to an end member 550lacking threads. Coupling member 552 further includes a contact portion554 along at least one side thereof. Contact portion 554 can be formedby a cutout providing a fiat surface extending along coupling member552. Contact portion 554 can also include a concave surface, a convexsurface, a receptacle, or other suitable configuration for contacting anengaging member. The thread pattern of coupling member 552 can extendcompletely therearound between the opposite sides of contact portion554. Other embodiments contemplate that multiple contact portions areprovided along coupling member 552 to provide multiple engagementlocations for engaging member 543, as discussed further below.

Coupling body 534 can be enlarged relative to rod portions 514, 532 toprovide an axial first bore 536 that threadingly receives the respectivecoupling members 516, 552. In the illustrated embodiment, coupling body534 is a cubic block, although other shapes are also contemplated, suchas rectangular, cylindrical and non-uniform shapes. First bore 536extends along and opens along longitudinal axes 513, 531 when alignedwith the respective rods 512, 530 at opposite ends of coupling body 534.Coupling body 534 further includes a first trans-axial bore 538 and anadjacent second trans-axial bore 539 extending therein transversely tolongitudinal axes 513, 531 and in communication with first bore 536.Bores 538, 539 can be internally threaded for receipt of respective onesof the engagement members 542, 543. Bores 538, 539 can be orthogonal tofirst bore 536, although other orientations are also contemplated.

Rods 512, 530 can be assembled in end-to-end fashion and aligned alonglongitudinal axes 513, 531 with coupling member 516 received in one endof bore 536 and coupling member 552 received in the opposite end of bore536. Coupling members 516, 552 are axially constrained by threadedengagement with coupling body 534. End members 520, 550 facilitatepositioning and alignment of coupling members 516, 552 in bore 536,preventing or reducing the possibility of cross-threading couplingmembers 516, 552 with coupling body 534. The axial load between rods512, 530 is carried by the engagement between coupling members 516, 552and coupling body 534, which are also aligned along the axes 513, 531when engaged. Accordingly, torsional loading of the components of rodsystem 510 is minimized since the rods 512, 530 are connected to oneanother in end-to-end fashion with axes 513, 531 aligned via couplingmechanism 528. Furthermore, the footprint of coupling mechanism 528 bothtransversely to rods 512, 530 and along rods 512, 530 is minimized,making the procedure for positioning rod system 510 less invasive,providing additional rod length for contouring and attachment offasteners for engagement with the spinal column, and minimizing thenumber of components employed in securing the rods 512, 530 to oneanother.

Engaging members 542, 543 are positionable in first trans-axial bore 538and second trans-axial bore 539 and engageable to respective ones of thecoupling members 516, 552 to prevent rods 512, 530 from disengaging fromcoupling body 534. In one embodiment, contact portion 518 of couplingmember 516 is oriented toward first trans-axial bore 538, and engagingmember 542 is an externally threaded set screw engageable in firsttrans-axial bore 538. Engaging member 542 is driven into firsttrans-axial bore 538 so that it is in contact with contact portion 518,preventing coupling member 516 from rotating in coupling body 534 andresisting torsional loading of rod 512. Similarly, contact portion 554of coupling member 552 is oriented toward second bore 539, and engagingmember 543 is an externally threaded set screw engageable in secondtrans-axial bore 539. Engaging member 542 is driven into bore 539 sothat it is in contact with contact portion 554, preventing couplingmember 552 from rotating in coupling body 534 and resisting torsionalloading of rod 530.

With contact surface 518 aligned with bore 538, the rod portion 514 isoriented in a predetermined alignment determined by the location ofcontact surface 518 and bore 538 relative to the respective rod portion514. Similarly, with contact surface 554 aligned with bore 539, the rodportion 532 is oriented in a predetermined alignment determined by thelocation of contact surface 554 and bore 539 relative to the respectiverod portion 532. For example, if one or both of rod portions 514, 532are provided with non-circular cross-sections, through-holes, or othercharacteristic along their respective lengths, the characteristics canbe oriented relative to contact surface 518, 554 and/or bores 538, 539so that engagement by the respective engaging members 542, 543 providesa desired alignment. The rod portions 514, 532 can be secured with thesecharacteristics in a predetermined alignment relative to one another,and maintained in this alignment by the engagement of engaging members542, 543 with contact surfaces 518, 554.

Referring to FIGS. 11 and 12, there is shown another embodiment a spinalrod system 560 including a first rod 562 and a second rod 580. First rod562 and second rod 580 are releasably coupled to one another inend-to-end fashion with a coupling mechanism 578.

Coupling mechanism 578 includes a coupling body 594 releasablyengageable to each of the first and second rods 562, 580. The couplingmechanism 578 is configured to secure rods 562, 530 to one another inend-to-end fashion with their longitudinal axes 563, 581 laterallyoffset from one another. This allows the relative positioning of rods562, 580 to be offset as may be desirable to accommodate the spinalanatomy while minimizing the footprint or intrusiveness of the couplingmechanism into the tissue surrounding the rod system, and maximizing thelength of the rod portion of each rod available for positioning and/orattachment along the spinal column.

Like rods 512, 530 discussed above, first rod 562 includes a first rodportion 564 and coupling member 566 at a first end of first rod portion564. Rod portion 564 extends from coupling member 566 to an oppositesecond end (not shown.) Second rod 580 includes coupling member 602 at afirst end thereof. Rod portion 582 extends from coupling member 602 toan opposite second end (not shown.) Rod portions 564, 582 can beprovided with characteristics that differ from one another.

As shown in FIGS. 11-12, rod portion 564 extends along longitudinal axis563 and includes a first cross-sectional dimension 572 between oppositesides thereof transverse to longitudinal axis 563. Similarly, rodportion 582 extends along longitudinal axis 581 and includes a secondcross-sectional dimension 590 between opposite sides thereof transverseto longitudinal axis 581. In the illustrated embodiment, cross-sectionaldimension 572 corresponds to a diameter of a cylindrical rod portion 564that is smaller than a diameter corresponding to cross-sectionaldimension 590 of a cylindrical rod portion 582. in still otherembodiments, the diameters of the rod portions 582, 564 are the same.

Coupling member 566 includes a threaded outer surface extending from rodportion 564 to an end member 570 lacking threads. Coupling member 566further includes a contact portion 568 along at least one side thereof.Contact portion 568 can be formed by a cutout providing a flat surfaceextending along coupling member 566. Contact portion 568 can alsoinclude a concave surface, a convex surface, a receptacle, or othersuitable configuration for contacting an engaging member. The threadpattern of coupling member 566 can extend completely therearound betweenthe opposite sides of contact portion 568.

Other embodiments contemplate that multiple contact portions areprovided along coupling member 566 to provide multiple engagementlocations for engaging member 592, as discussed further below.

Rod 580 similarly includes a coupling member 602 including a threadedouter surface extending from rod portion 582 to an end member 600lacking threads. Coupling member 602 further includes a contact portion604 along at least one side thereof. Contact portion 604 can be formedby a cutout providing a flat surface extending along coupling member602. Contact portion 604 can also include a concave surface, a convexsurface, a receptacle, or other suitable configuration for contacting anengaging member. The thread pattern of coupling member 602 can extendcompletely therearound between the opposite sides of contact portion604. Other embodiments contemplate that multiple contact portions areprovided along coupling member 602 to provide multiple engagementlocations for engaging member 593, as discussed further below.

Coupling body 594 can be enlarged relative to rod portions 564, 582 toprovide an axial first bore 596 that threadingly receives couplingmember 566, and an axial second bore 597 offset laterally from andextending parallel to first bore 596 to threadingly receive couplingmember 602. In the illustrated embodiment, coupling body 594 is arectangular block, although other shapes are also contemplated, such ascubic, cylindrical and non-uniform shapes.

First bore 596 extends along and opens on longitudinal axis 563 whenaligned with rod 562, and second bore 597 extends along and opens onlongitudinal axis 581 when aligned with rod 580. Coupling body 594further includes a first trans-axial bore 598 and an adjacent secondtrans-axial bore 599 extending therein transversely to respective onesof the longitudinal axes 563, 581 and in communication with respectiveones of the bores 596, 597. Bores 598, 599 can be internally threadedfor receipt of respective ones of the engagement members 592, 593. Bores598, 599 can be orthogonal to the respective bores 596, 597, althoughother orientations are also contemplated.

Rods 562, 580 can be assembled in end-to-end fashion with couplingmember 566 received in first bore 596 and coupling member 602 receivedin second bore 597. Coupling members 566, 602 are axially constrained bythreaded engagement with coupling body 594. End members 570, 600facilitate positioning and alignment of coupling members 566, 602 inbores 596, 597, preventing or reducing the possibility ofcross-threading coupling members 566, 602 with coupling body 594. Theaxial load between rods 562, 580 is carried by the engagement betweencoupling members 566, 602 and coupling body 594.

The axial restraint provided by the threaded engagement of rods 562, 580to coupling body 594 allows the length of coupling body 594 along axes563, 581 to be minimized, thus minimizing its intrusion into theadjacent anatomy and maximizing the rod length available for attachmentof connection elements. The lateral offset provided by couplingmechanism 578 allows application of rods 562, 580 in anatomicallocations where alignment of axes 563, 581 would not be optimal.Engaging members 592, 593 are positionable in first trans-axial bore 598and second trans-axial bore 599, respectively, and engageable torespective ones of the coupling members 566, 602 to contact the alignedcontact portions 568, 604 to prevent rods 562, 580 from disengaging fromcoupling body 594.

FIGS. 13-14 shown another embodiment connection assembly 610 similar tothe embodiment shown in FIGS. 1-2, except for rods 612, 630 having thesame cross-sectional dimension 622 transversely to longitudinal axes613, 631. Rods 612, 630 are coupled to one another in end-to-end fashionwith longitudinal axis 613, 631 aligned with one another. Rod 612includes a rod portion 614, a coupling member 616 having externalthreads, a contact portion 618 along coupling member 616, and an endmember 620. Rod 630 includes a rod portion 632 providing a couplingmechanism 628 having a coupling body 634 integrally formed with rodportion 632. Coupling body 634 includes an axial bore to threadinglyreceive coupling member 616. Engaging member 642 is threadingly receivedin trans-axial bore 638 to engage rod 612 at contact surface 618 andprevent it from rotating in coupling body 634.

FIGS. 15-16 shown another embodiment rod connection assembly 660 similarto the embodiment shown in FIGS. 9-10, except for rods 662, 680 havingthe same cross-sectional dimension 672 transversely to longitudinal axes663, 681. Rods 662, 680 are coupled to one another in end-to-end fashionwith longitudinal axis 663, 681 aligned with one another. Rod 662includes a rod portion 664, a coupling member 667 having externalthreads, a contact portion 668 along coupling member 667, and an endmember 670. Similarly, rod 680 includes a rod portion 682, a couplingmember 702 having external threads, a contact portion 704 along couplingmember 702, and an end member 700. A coupling mechanism 678 includescoupling body 684 with an axial passage 686 to threadingly engagecoupling members 667, 702 in end-to-end fashion with axis 663, 681aligned with one another. Engaging members 692, 693 are threadinglyreceived in respective ones of trans-axial bores 688, 689 to engage therespective coupling members 667, 702 and prevent rotation of rods 662,680 in coupling body 684.

FIGS. 17-18 shown another embodiment rod connection assembly 710 similarto the embodiment shown in FIGS. 11-12, except for rods 712, 730 havingthe same cross-sectional dimension 722 transversely to longitudinal axes713, 731. Rods 712, 730 are coupled to one another in end-to-end fashionwith longitudinal axis 713, 731 laterally offset from one another. Rod712 includes a rod portion 714, a coupling member 716 having externalthreads, a contact portion 718 along coupling member 716, and an endmember 720. Similarly, rod 730 includes a rod portion 732, a couplingmember 752 having external threads, a contact portion 754 along couplingmember 752, and an end member 750. A coupling mechanism 728 includescoupling body 734 with axial passages 736, 737 to threadingly engagecoupling members 716, 752 in end-to-end fashion with axes 713, 731offset laterally relative to one another. Engaging members 742, 743 arethreadingly received in respective ones of trans-axial bores 738, 739 toengage the respective coupling members 716, 752 at contact surfaces 718,754 and prevent rotation of rods 712, 730 in coupling body 734.

FIG. 19 illustrates another embodiment of the spinal construct systemhaving a spinal fixation plate 760 coupled to a fixture element 762 inend-to-end fashion. The spinal fixation plate 760 may include at leastone bore 768 sized to accept a bone anchoring component 764. A malecoupling member 776 extends outward from an edge of the plate 760. Themale coupling member 776 comprises an externally threaded surface 778and a non-threaded contact surface 780 along at least one side thereof.As described above, the contact surface may be substantially flattened.

The fixture element 762 includes a female coupling body 782 having afirst bore 784 that receives the male coupling member 776. The firstbore 784 may be internally threaded to engage the externally threadedsurface 778 of the male coupling member 776. This connection resistsaxial displacement of the spinal fixation plate 760 relative to thefixture element 762. The female coupling body 782 further has a secondbore 786 extending through the coupling body 782 transverse to the firstbore 784 and in communication with the first bore 784. An engagementmember 788 is disposed in the second bore 786 and engages the contactsurface 780 so as to resist relative rotation between the spinalfixation plate 760 and the fixture element 762. The second bore 786 maybe internally threaded and the engagement member 788 may be externallythreaded for threaded engagement in the second bore.

The spinal fixation plate 760 and the fixture element 762 illustrated inthe embodiment of FIG. 19 are axially aligned about a commonlongitudinal axis. In another embodiment, the two elements may belaterally offset about a common longitudinal axis, similar to theembodiments illustrated in FIGS. 17 and 18. FIGS. 20A and 20B illustrateembodiments having a longitudinal axis of the plate 760 offset from anaxis of the fixture element 762.

The embodiments of FIG. 19, 20A, and 20B each include the femalecoupling body 782 associated with the fixture element 762. In otherembodiments, the female coupling body 782 may be associated with thespinal fixation plate 760.

FIG. 21-23 illustrate embodiments having a coupling body 816 thatcouples spinal fixation plate 790 to fixture element 792. The spinalfixation plate 790 has a first male coupling member 794 extending froman edge thereof. The first male coupling member 794 comprises a firstexternally threaded surface 796 and a first non-threaded contact surface798 along at least one side thereof. The spinal fixation plate 790 may,as appropriate, include one or more bone anchoring components 800 ortransverse bore(s) 802 for accepting bone anchoring components 800.

The fixture element 792 may have a second male coupling member 804extending from a first end thereof. The second male coupling member 804comprises a second externally threaded surface 806 and a secondnon-threaded contact surface 808 along at least one side thereof.Embodiments of the fixture element 792 comprise a second spinal fixationplate 810 (FIG. 21), an aligned elongated rod 814 (FIG. 22), or anoffset elongated rod (FIG. 23).

A female coupling body 816 couples the spinal fixation plate 790 to thefixture element 792 in end-to-end fashion so as to resist axialdisplacement of said spinal fixation plate 790 relative to the fixtureelement 792. The female coupling body 816 has a first bore 818 thatreceives the first male coupling member 794. The female coupling body816 has a second bore 820 extending transverse to the first bore 818 andin communication with the first bore 818. The second bore 820 may beinternally threaded and the engagement member 822 may be externallythreaded for threaded engagement in the second bore 820. An engagementmember 822 contacts the first contact surface 798 so as to resistrelative rotation between the spinal fixation plate 790 and the fixtureelement 792.

A third bore 824 is also included in the female coupling body 816 toreceive the second male coupling member 804. The female coupling body816 may advantageously also include a fourth bore 826 transverse to thethird bore 824 and in communication with the third bore 824. A secondengagement member 822 is disposed in the fourth bore 826 to contact thesecond contact surface 808 so as to resist relative rotation between thefixture element 792 and the spinal fixation plate 790. The third bore824 may be parallel, aligned, or offset to the first bore 818 so thatthe spinal fixation plate 790 and the fixture element 792 may be axiallyaligned about a common longitudinal axis or laterally offset about acommon longitudinal axis, as is desired.

In the embodiments illustrated in FIGS. 19-24, the male members compriseexterior threaded surfaces that engage with corresponding threadedsurfaces of the female member. In another embodiment, the members arenot threadingly engaged. The members may be maintained in position bylocking elements such as the engagement members, adhesives, or othersources.

In one embodiment, the coupling body 816 includes male members thatextend outward from the body and engage with corresponding femalemembers in the elements.

In an alternative embodiment, the spinal fixation plate may comprise aspinal fixation block 772 as illustrated in FIG. 24. Such a spinalfixation block 772 may include a transverse bore 768 for accepting abone anchoring component 764.

The present invention may be carried out in other specific ways thanthose herein set forth without departing from the scope and essentialcharacteristics of the invention. The present embodiments are,therefore, to be considered in all respects as illustrative and notrestrictive, and all changes coming within the meaning and equivalencyrange of the appended claims are intended to be embraced therein.

1-22. (canceled)
 23. A spinal construct system comprising: a spinalfixation member including an elongated shape with a surface sized to lieagainst a portion of a spinal column; a fixture element coupled to saidspinal fixation member in end to end fashion; a male coupling memberassociated with one of said spinal fixation member and said fixtureelement; a female coupling body associated with the other of said spinalfixation member and said fixture element; said female coupling bodycomprising a first bore receiving said male coupling member so as toresist axial displacement of said spinal fixation member to said fixtureelement; said female coupling body further comprising a second boreextending through said coupling body transverse to said first bore andin communication with said first bore; and an engaging member disposedin said second bore and engaging said male coupling member so as toresist relative rotation between said spinal fixation member and saidfixture element.
 24. The expandable implant of claim 23, wherein thefixture element is an elongated rod.
 25. The expandable implant of claim23, wherein the spinal fixation member is an elongated rod.